You could always talk to it as a Sybase DB, since MSSQL (up to 6.5 anyways, and 7.0 is compatible) is really a Sybase DBMS covered in Microsoft gooey dressing.
Make sure you are using the Sybase libraries, or there will be trouble. This works fine from Linux with sybase-ct compiled in and Sybase-ASE drivers in /home/sybase. I assume the Sybase DLL under NT will perform as well or better than ODBC as the sybase-ct code under Linux beats ODBC in speed from what I can tell.
$dbms = "dns.server.name";
$user = "username";
$pass = "password";
$cs = sybase_connect($dbms, $user, $pass);
sybase_query("USE databasename", $cs);
or
sybase_select_db("databasename", $cs);
$rs = sybase_query("SQL", $cs);
$result_array = sybase_fetch_array($cs);
sybase_free_result($rs);
sybase_close($cs);
Give that a try, that's what we use on our website against an MSSQL 6.5 NT box. Tis quick too. (not as fast as MySQL, but I love my triggers and stored procedures, NT hohum)
Chris